Detection of high-frequency tensile vibrations of a fault during shear rupturing: observations from the 2008 West Bohemia swarm

0363813 - GFÚ 2012 RIV GB eng J - Journal Article
Vavryčuk, Václav
Detection of high-frequency tensile vibrations of a fault during shear rupturing: observations from the 2008 West Bohemia swarm.
Geophysical Journal International. Roč. 186, č. 3 (2011), s. 1404-1414. ISSN 0956-540X. E-ISSN 1365-246X
R&D Projects: GA AV ČR IAA300120801
Institutional research plan: CEZ:AV0Z30120515
Keywords : earthquake dynamics * earthquake source observations * body waves * dynamics and mechanics of faulting
Subject RIV: DC - Siesmology, Volcanology, Earth Structure
Impact factor: 2.420, year: 2011

The analysis of 12 earthquakes of magnitudes between 1.7 and 3.7 that occurred in 2008 in West Bohemia, Czech Republic reveals that shear rupturing along a fault is accompanied by weak tensile vibrations of the fault. The vibrations are of a narrow frequency band with frequencies distinctly higher than those of shear rupturing. The tensile vibrations decay slowly in time and often resemble resonant waves. They complicate the radiated P waveforms and the P-wave radiation pattern. The tensile vibrations can be observed in waveforms in directions near the nodal lines where the dominance of shear-faulting radiation is lost. The tensile vibrations are probably generated by opening of the fault during shear rupturing or by creating a wing tensile crack at the tip of the fault when shear fracturing stops.
Permanent Link: http://hdl.handle.net/11104/0199469